i(3)so3-galactosylceramide and Carcinoma--Hepatocellular

Cholangiocarcinoma (CCA) is a malignancy arising from the bile duct epithelium and has a poor outcome. Sulfatides are lipid components of lipid rafts, and are implicated in several cancer types. In the liver, sulfatides are specifically present in the bile ducts. Here, sulfatide abundance and composition were analyzed using mass spectrometry imaging in intrahepatic CCA (iCCA) tumor tissue, and correlated with tumor biology and clinical outcomes.. Sulfatides were analyzed in iCCA (n = 17), hepatocellular carcinoma (HCC, n = 10) and colorectal liver metastasis (CRLM, n = 10) tumor samples, as well as tumor-distal samples (control, n = 16) using mass spectrometry imaging. Levels of sulfatides as well as the relative amount in structural classes were compared between groups, and were correlated with clinical outcomes for iCCA patients.. Sulfatide localization was limited to the respective tumor areas and the bile ducts. Sulfatide abundance was similar in iCCA and control tissue, while intensities were notably higher in CRLM in comparison with control (18-fold, P < 0.05) and HCC tissue (47-fold, P < 0.001). Considerable variation in sulfatide abundance was observed in iCCA tumors. A high ratio of unsaturated to saturated sulfatides was associated with reduced disease-free survival (10 vs. 20 months) in iCCA. The sulfatide pattern in HCC deviated from the other groups, with a higher relative abundance of odd- versus even-chain sulfatides.. Sulfatides were found in tumor tissue of patients with iCCA, with sulfatide abundance per pixel being similar to bile ducts. In this explorative study, sulfatide abundance was not related to overall survival of iCCA patients. A high ratio of unsaturated to saturated sulfatides was associated with earlier tumor recurrence in patients with iCCA.

Topics: Bile Duct Neoplasms; Bile Ducts, Intrahepatic; Carcinoma, Hepatocellular; Cholangiocarcinoma; Disease-Free Survival; Humans; Liver Neoplasms; Sulfoglycosphingolipids

LncRNA (long noncoding RNA) is often dysregulated in tumors especially hepatocellular carcinoma (HCC). However, the dysregulation mechanism of lncRNAs is largely unknown. Here, we showed that lncRNA lncAY expression was stimulated in HCC by either endogenous or exogenous sulfatide. Elevated lncAY promoted HCC cell migration or angiogenesis, whereas lncAY silence suppressed HCC cell migration and proliferation. Interestingly, the activity of lncAY gene promoter was enhanced by sulfatide. Then Myb and MEF2C were identified as the transcription factors responsible for the stimulation of lncAY promoter activity and transcription by sulfatide. Both Myb and MEF2C enrichment on lncAY promoter was further confirmed, and their occupancy on lncAY promoter was strengthened by sulfatide for Myb or MEF2C was acetylated. Mutant Myb-K456A exhibited reduced acetylation and weak stimulation for lncAY transcription. However, Myb mutation K456/503A prevented Myb from acetylation induced by sulfatide. The mutant Myb K456/503A further was unable to occupy lncAY promoter and enhance lncAY transcription. In conclusion, this study demonstrated lncAY transcription was abnormally upregulated by sulfatide in HCC through Myb/MEF2C to promote HCC progression.

Topics: Acetylation; Carcinoma, Hepatocellular; Cell Line, Tumor; Gene Expression Regulation, Neoplastic; Humans; Liver Neoplasms; MEF2 Transcription Factors; Proto-Oncogene Proteins c-myb; RNA, Long Noncoding; Sulfoglycosphingolipids

N6-Methyladenosine (m6A), one of the post-transcriptional modifications of RNA, is important in hepatocellular carcinoma (HCC). However, the mechanism of its regulation remains elusive. We here show that exposure of HCC cells to sulfatide significantly reduced the total mRNA m6A modification. Interestingly, METTL3 protein was robustly acetylated and the binding of METTL3 to MTF1 mRNA, METTL14 or WTAP was weakened in cells treated with sulfatide. Further investigation of the METTL3 complex revealed recruitment of the deacetylase scaffold SIN3B, but a diminished level of histone deacetylase HDAC2, which might enhance the acetylation of METTL3. The m6A abundance in MTF1 mRNA was markedly decreased in cells after sulfatide treatment. The expression of MTF1, a zinc-dependent transcription factor, was significantly strengthened with reduced m6A modification. Sulfatide prolonged the half-life of MTF1 mRNA, while the mutation (A to C) on 7 methylation sites in the 3'UTR of MTF1 mRNA enhanced MTF1 mRNA stability. 3-deaza-adenosine, an m6A methylation inhibitor, significantly reduced the m6A modification of MTF1 mRNA but extended its half-life time. Importantly, overexpression of MTF1 prompted HCC cell proliferation and was associated with poor prognosis. In conclusion, the METTL3-METTL14-WTAP complex was regulated by acetylation induced by sulfatide to control MTF1 m6A methylation and its mRNA transcription, which was important for the tumor growth and migration of HCC.

Topics: Acetylation; Adenosine; Carcinoma, Hepatocellular; Humans; Liver Neoplasms; Methyltransferases; RNA, Messenger; Sulfoglycosphingolipids

Paired amphipathic helix protein (SIN3B) is a transcription corepressor for many genes. Here we show a different regulation mechanism of integrin αV gene expression by SIN3B in human hepatocellular carcinoma (HCC). We first observed a close relationship between Integrin αV and SIN3B expressions in HCC patients and tumor cell lines with different metastatic potentials. Overexpression of SIN3B significantly accelerated the cell migration rate of SMMC-7721, but failed when integrin αV expression was silenced. Interestingly, SIN3B stimulated integrin αV subunit promoter activity only in the presence of sulfatide. Importantly, SIN3B was identified in the complex with sulfatide by mass spectrometry. Fat blot assay indicated that SIN3B specifically interacted with sulfatide. Molecular modeling suggested that sulfatide induced the conformational change of SIN3B from compacted α-helices to a relaxed β-sheet in PAH2 domain. The data of immunoprecipitation and ChIP assay indicated that altered SIN3B lost the binding affinity with MAD1 and HDAC2, which reduced the recruitment of HDAC2 on integrin αV gene promoter and prevented the deacetylation of the histone 3. In conclusion, this study demonstrated that SIN3B promoted the transcriptional activation of the integrin αV subunit gene promoter by reducing interaction with HDAC2.

Topics: Acetylation; Carcinoma, Hepatocellular; Cell Cycle Proteins; Cell Line, Tumor; Cell Movement; Histone Deacetylase 2; Histones; Humans; Integrin alphaV; Liver Neoplasms; Molecular Dynamics Simulation; Promoter Regions, Genetic; Protein Binding; Protein Structure, Secondary; Protein Subunits; Repressor Proteins; Sulfoglycosphingolipids; Transcription, Genetic

Integrin αV gene expression is often dysregulated in cancers especially in hepatocellular carcinoma (HCC); however, the mechanism of regulation is poorly understood. Here, it is demonstrated that sulfatide activated integrin αV gene transcription, through histone H3K9/14 acetylation at the promoter, and high integrin αV expression are closely associated with poor prognosis. To elucidate the mechanism of regulation of acetylation, sulfatide-bound proteins were screened by mass spectrometry (MS), and bromodomain containing protein 1 (BRD1) was identified as an interacting protein that also colocalized with sulfatide in HCC cells. BRD1 was also formed a complex with Sp1, which was recruited to the integrin αV gene promoter. Sulfatide was also found to induce BRD1, monocytic leukemia zinc finger (MOZ) and histone acetyltransferase binding to ORC1 (HBO1) acetyltransferase multiprotein complex recruitment to the integrin αV promoter, which is responsible for histone H3K9/14 acetylation. Finally, knockdown of BRD1 limited sulfatide-induced H3K9/14 acetylation and occupancy of MOZ or HBO1 on integrin αV gene promoter.

Topics: Acetylation; Carcinoma, Hepatocellular; Cell Line, Tumor; Female; Gene Expression Regulation, Neoplastic; Histone Acetyltransferases; Histone Chaperones; Humans; Integrin alphaV; Liver Neoplasms; Male; Models, Molecular; Neoplasm Metastasis; Nuclear Proteins; Prognosis; Sulfoglycosphingolipids; Survival Analysis; Tissue Array Analysis; Up-Regulation

Integrin αVβ3 is a malignant driver of anchorage-independence and tumor angiogenesis, but its dysregulation in hepatocellular carcinoma (HCC) remains unclear. In this study, we observed that sulfatide significantly promoted integrin αV(ITGAV) expression and wound closure in HCC. We also noted that elevated sulfatide profoundly stimulated integrin αVβ3 clustering and signaling. In the cells with integrin αVβ3 clustering induced by sulfatide, integrin β3 subunit was phosphorylated. Simultaneously, focal adhesion kinase (FAK), Src and paxillin were also phosphorylated. Treatment with FAK inhibitor resulted in robust suppression of FAK-Y397 and Src-Y416 phosphorylation stimulated by sulfatide, but not suppression of integrin β3 phosphorylation. Src inhibitors repressed Src-Y416 and FAK Y861 and Y925 phosphorylation, but not FAK-Y397 and integrin β3 phosphorylation. After mutation of integrin β3 (Y773F and Y785F), FAK or Src phosphorylation failed to be stimulated by sulfatide. Moreover, β3 Y773 and Y785 phosphorylation was suppressed by insulin-like growth factor receptor knockdown even in cells stimulated by sulfatide. In assays of immunoprecipitation and immunostaining with integrin αV or β3 antibody, labeled sulfatide was found in the complex and co-localized with integrin αVβ3. Taken together, this study demonstrated that elevated sulfatide bound to integrin αVβ3 and induced clustering and phosphorylation of αVβ3 instead of matrix ligand binding, triggering outside-in signaling.

Topics: Blotting, Western; Carcinoma, Hepatocellular; Cell Line, Tumor; Focal Adhesion Protein-Tyrosine Kinases; Gene Expression Regulation, Neoplastic; Humans; Integrin alphaVbeta3; Liver Neoplasms; Paxillin; Phosphorylation; Protein Binding; Reverse Transcriptase Polymerase Chain Reaction; Signal Transduction; src-Family Kinases; Sulfoglycosphingolipids; Tyrosine

The biological relevance and regulation mechanism of aberrant miR-223 expression in human hepatocellular carcinoma (HCC) remain unknown. Our aim was to investigate miR-223 regulation in HCC.. miR-223 and integrin αV dysregulation were verified in 57 HCC specimens. Immunohistochemical analysis of integrin αV and sulfatide levels was performed on another cohort of 103 HCC samples. Epigenetic analysis was used to explore the effect of sulfatide on miR-223 transcription. Orthotopic growth, and intrahepatic and pulmonary metastasis of tumors derived from SMMC-7721 cells expressing miR-223 or cerebroside sulfotransferase were monitored in mice.. miR-223 was reduced in HCC specimens and highly metastatic cell lines. Enhanced miR-223 expression had a negative effect on integrin αV-mediated cell migration. In vivo assays of metastasis in an orthotopically implanted model demonstrated that miR-223 effectively inhibited HCC metastasis. Further analysis demonstrated that integrin αV is negatively regulated by miR-223. Moreover, the integrin αV subunit was significantly positively correlated with highly expressed sulfatide in 103 HCC specimens. Intriguingly, miR-223 expression was suppressed by sulfatide in HCC in association with reduced recruitment of acetylated histone H3 and C/EBPα to the pre-miR-223 gene promoter, where monocytic leukemia zinc finger (MOZ) protein, a MYST-type histone acetyltransferase, lost its attachment. The expression of histone deacetylases, HDAC9 and HDAC10, were greatly stimulated by sulfatide and their recruitment to miR-223 gene promoter was enhanced.. Downregulation of miR-223 in HCC is associated with the epigenetic regulation by highly expressed sulfatide and involved in tumor metastasis.

Topics: Animals; Carcinoma, Hepatocellular; Cell Line, Tumor; Cell Movement; Down-Regulation; Epigenesis, Genetic; Gene Expression Regulation, Neoplastic; Heterografts; Humans; Integrin alphaV; Liver Neoplasms; Mice; Mice, Nude; MicroRNAs; Neoplasm Metastasis; Promoter Regions, Genetic; RNA, Neoplasm; Sulfoglycosphingolipids

Lactosylsulfatide (SM3), one of the major sulfated glycolipids, has been reported to be involved in cellular adhesion. Yet, its specific function has not been well understood in tumor biology, especially in the process of metastasis. We analyzed expression levels of sulfatide on HCC cells with different metastatic potentials and found that levels were correlated with metastatic potential. Next, the cerebroside sulfotransferase (CST) (EC2.8.2.11) gene, which synthesizes SM3 as well as galactosylsulfatide (SM4), was transfected into the HCC line Hep3B. Cell surface expression of SM3 was confirmed by thin-layer chromatogram immunostaining and flow-cytometric analyses. SM3-expressing Hep3B cells showed elevated expression of integrin alphaVbeta3 and higher adhesive ability to vitronectin compared to mock cells. Furthermore, SM3 expression promoted intrahepatic metastasis in nude mice. Thus, SM3 may play an important role in the metastasis of HCC cells by causing the interaction of integrin alphaVbeta3 with vitronectin.

Topics: Animals; Carcinoma, Hepatocellular; Cell Adhesion; Glycolipids; Integrins; Liver Neoplasms, Experimental; Mice; Mice, Nude; Sulfoglycosphingolipids; Sulfotransferases; Tumor Cells, Cultured; Vitronectin